I reset the rough pump for George, and apparently
it tripped again. The first time it tripped, it was hot
when he told me about it, so it likely tripped while he
was using it. That could also be the case the second
time, but I wasn't here.
Things I've noticed: The oil demister had a lot of oil
in it (about a pint, and there's still more in there).
We increased the pump ballast from about 100 mT
to 300mT with the new pump.
New pump was installed about a month ago.
Pump oil level was fine.
So, I drained some oil from the demister, lowered
the ballast back to 100-120 mT, and reset it
a second time. I put it through several pumpdowns from
atmosphere with no trip, and then let it run. Still
no trip. So it seems to be running ok. Maybe the user
was opening the roughing valve too fast (??). Perhaps
that could cause oil to "slug" into the demister, and cause
an overlaod to trip the breaker (??).
Unrelated note: I noticed that the power supply (for the
sputter guns, upstairs in the lab) is making noise. It sounds
to me like the cooling fan. This is external to the supply,
and we could probably get a backup fan ordered fairly
easily.
Everything seems ok as of 09:30 on Monday, so for now
maybe we should just keep a close eye on it. Some users
are scheduled for today, so we should be able to see if
it is ok or not.
-Eric